1. Description of the Related Art
The present invention relates to a starting control unit and the start command signal generation apparatus therefor; in the starting control unit, in order to suppress a starting current, electric power is supplied to the starter motor by way of a current suppression resistor for a predetermined time immediately after the engine has been started.
2. Description of the Related Art
There is utilized a timer circuit for current-limiting starting in which, in order to suppress an excessive starting current at a time when the engine is started and an abnormal drop of the power-source voltage caused by the internal resistance of the vehicle battery and the resistance of a wiring lead, the current suppression resistor is connected in series with the starter motor when the engine is started, and at a time that is a predetermined time after the driving current is attenuated as the rotation speed of the starter motor rises, the current suppression resistor is short-circuited by the output contact of a short-circuiting relay. For example, Patent Document 1 discloses an engine starting apparatus incorporating a starter motor, a fixed resistor connected in series with a current path including an electromagnet shift switch that energizes the starter motor, an opening/closing means that performs short-circuiting control of the fixed resistor, and a delayed-activation means that activates the opening/closing means in a delayed manner; the delayed-activation means is formed of a timer circuit that operates after receiving the output voltage of the electromagnet shift switch.
Moreover, Patent Document 2 discloses a starter including an electromagnetic switch that performs opening and closing of a main contact provided in a motor circuit, a current suppression resistor connected in series with the main contact provided in the motor circuit, a short-circuiting relay that is provided in such a way as to be able to short-circuit the current suppression resistor, and a timer circuit that activates the short-circuiting relay in a delayed manner; the timer circuit sets a delay time between a time instant when the electromagnet switch is energized and a time instant when the short-circuiting relay is energized; the delay time is set in such a way that the value of the maximum current that flows in the motor when the short-circuiting relay is energized becomes the same as or smaller than the value of the maximum current that flows in the motor when the electromagnet switch is energized.
Furthermore, Patent Document 3 discloses a starter in which there are separately provided an excitation coil that pushes out a pinion gear toward a ring gear and a switch coil that is energized when a predetermined time elapses after the excitation coil is energized and that performs circuit-closing drive of the main contact of a motor circuit, and after the pinion gear and the ring gear have securely been engaged with each other, the main contact is closed.
Still moreover, according to Patent Document 4, in order to enable the starting of an engine to continue even when the operation of a central processing unit is interrupted due to a voltage drop at a time when the engine is started, a driving circuit makes a starter relay turn on so as to make a starter operate, when a microcomputer of an ECU (engine control apparatus) detects that a starting switch has turned on; the coil of the starter relay is energized also by way of the starting switch and a normally closed relay; and in the ECU, there is provided a circuit that turns off the normally closed relay in response to a signal from the microcomputer. Accordingly, even when the operation of the microcomputer is interrupted by a voltage drop, the starter relay is kept on, as long as the starting switch is on. When determining that the operation of the starter is not necessary, the microcomputer is required only to turn off the normally closed relay.